The ultimate objective of the proposed research is to develop bioerodible polymer-drug implants that can be used for either long-term systemic or localized drug delivery. The specific aims of the Phase I program involve characterizing the drug loading and drug molecular weight range that can be used with a newly developed class of bioerodible hydrogels. The Phase I program includes synthesis of several types of these polymers containing drugs with a range of molecular weights, and subsequent determination of drug-release kinetics in vitro. It is expected that the results of this work will define both the lowest molecular weight and highest loading of drugs that can be released by erosion of the polymer. This will enable the selection of specific drug/polymer products to be developed and tested both in vitro and in vivo in Phase II. These products could include such commercially important drugs as human growth hormone, LHRH, calcitonin, insulin, interferon, heparin, enzymes, antibiotics, antineoplastics, antigens, and narcotic antagonists. The development of bioerodible implants containing such drugs could result in dramatically improved drug efficacy with the avoidance of many undesirable side-effects.